K-9 skull study may help children with craniofacial deformities

Bethesda
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The family dog may be more than a fun and faithful companion; in fact, researchers believe dogs may help lead us to a better understanding of our heads.

Jeffrey Schoenebeck, PhD and Elaine Ostrander, PhD, from National Human Genome Research Institute (NHGRI), have released a study that shows over the course of history, human involvement in the breeding of canines has impacted the shape of dogs' skulls. By studying these variations and the genes of these dogs, researchers believe they can gain insight into the development of human skulls, perhaps leading to new ways of understanding and treating craniofacial disorders.

According to a Science Alerts article, the craniofacial diversity of dogs is the result of thousands of years of human intervention in the natural selection of breeding. Until recently, little was known about the "genetic underpinnings" that allows us to determine the evolution and shape of a dog's skull. That has now changed however.

The shape of the skull, whether in canines or humans, is a complex trait that involves many different genes and gene interactions. However, since there are standardized traits for more than 400 breeds of dogs, each with a distinct set of defined traits for the skull's bone structure, researchers can now look at those traits and see how selective breeding has influenced those traits.

For example, scientists looked at the genes that cause Bulldogs and Pugs to have short faces, as well as the genes that lead to the narrow, elongated face of a Collie. They also looked at the genes of dogs that fall somewhere in the middle of the extremes, such at the rounded skull of a Chihuahua and the downward slanting nose of the Bull Terrier.

Using what is known as genome-wide association studies (GWAS) and the developments in canine genome mapping, researchers looked at the genes and use of selective breeding to determine how it has impacted the skull shape and development of canines of the years. Their hope is that the study, entitled The Genetics of Canine Skull Shape Variation, will allow them to more fully understand how craniofacial development in dogs can advance the study of human health and development.

Craniofacial diversity exists between and within breed dogs. White strips highlight the palate (left) and brainstem (right) in each skull example.

Nussbaumer

Although researchers admit that using the "dog model" is "young in human years", they believe a better understanding of the genes in canines will help to explain how craniofacial defects occur in humans. Schoenebeck told Science Daily:

"We may find new roles for genes, never before implicated in cranium development."

According to Ostrander, by identifying how different genetic mechanisms cause various canine skull shapes, researchers can use that knowledge to study human cranial abnormalities. She went on to say:

"[This is] a way to figure out what sort of genetic variation matters and what doesn't.”

According to the researchers, the insight gained through this study will enable scientists to:

"work towards assembling the full inventory of genes associated with vertebrate cranioskeletal shape, in turn illuminating evolutionary conserved mechanisms of cranioskeletal development in our own species."